Is Agoras scalable? Is it easier to deal with scalability issue with Tau?
any scalability (or other) solution to be found in the future, can be applied. that's the essence of being a self-amending system, and that's why there cannot be competitors to such a system 
That sounds good. Will Agoras use a PoS or PoW consensus mechanism?
quite same answer: this can also change.
however me personally not aware of a sound scheme as pow.
as a small example, how can security grow with time under pos? looks like it remains fixed. unless high inflation is considered, and even though, it wont grow linearly as in pow
